712 THE POPULAR SCIENCE MONTHLY. 



not come to interfere with life and health. In a moment, if you choose, 

 I will make them ill, all these little beings. 



We have not finished with the peculiarities of our experiment, 

 which will appear the more remarkable and instructive as you study 

 it more closely. Let us weigh the vibrios that have been formed when 

 the process ceases, when all internal movement has disappeared, and 

 when they have fallen inert to the bottom of the flask, because they 

 have exhausted their principal food, the lactic acid, transforming it 

 into butyric acid, which is absolutely unfit for their existence, you 

 will know why in a moment when I describe fermentible materials. 

 Let us compare this weight of the vibrios with that of the 75 grammes 

 of the transformed lactate of lime. The difference is considerable. I 

 cannot now give you the exact figures, but the proportion is at the 

 most as 1 to 200. What does that mean ? an agent which causes the 

 decomposition of a weight of matter 200 times as great as itself! But 

 that is the characteristic of the phenomena to which chemists have 

 given the narae phenomefia of fermentation. Yes, we have had to do 

 with a real fermentation, in which the lactic acid is the ferraeating 

 substance and the vibrios the ferment. 



Who would dare now to maintain that fermentations are phe- 

 nomena of contact, phenomena of movement communicated by an al- 

 buminoid substance which is undergoing change, or of phenomena 

 produced by semi-organized substances which are being transformed 

 into this or into that ? All these scaflToldings built by the imagination 

 crumble before our experiment, so simple and so demonstrative. 



Still, the most essential and, so to speak, dominant circumstance 

 in our experiment has not yet been introduced, and it is time for me 

 to submit it to your attention. 



We prepared at the beginning a nutritive liquid, deprived entirely 

 of air and protected from contact with it ; we then sowed vibrios in it, 

 and, during the weeks that have elapsed, our liquid has never been un- 

 covered. Nevertheless, the vibrios have multiplied infinitely. Here, 

 then, is life that is to say, nutrition and generation without the 

 slightest aid from air or free oxygen. And in this experiment two 

 things have marched side by side, life without air and fermentation. 

 Ah, if that was a general phenomenon; if life as we kn(fvv it, with ab- 

 sorption of free oxygen, was not accompanied by fermentation properly 

 so called ; if the weight of assimilated food corresponded to that of 

 food ingested and used under the influence of respiration; and if, on 

 the other hand, life without air was always associated with fermenta- 

 tion ; if, in the latter case, life resulted in the transformation of an 

 enormous weight of food as compared with the weight of the nutritive 

 assimilation should we not have raised the veil of these mysterious 

 phenomena of fermentation ? 



From the moment it should be established that there is correlation 

 between the fact of life without air and the fact of fermentation, 



